Advanced simultaneous activation algorithm

ABSTRACT

An electrosurgical generator includes: a power supply configured to output a DC waveform; a power converter coupled to the power supply and configured to generate a radio frequency waveform based on the DC waveform; an active terminal coupled to the power converter and configured to couple to a first electrosurgical instrument and a second electrosurgical instrument; at least one sensor coupled to the power converter and configured to sense at least one property of the radio frequency waveform; and a controller coupled to the power converter. The controller is configured to: determine a first impedance associated with a first electrosurgical instrument and a second impedance associated with a second electrosurgical instrument based on the at least one property of the radio frequency waveform; and adjust at least one parameter of the radio frequency waveform based on the first impedance and the second impedance.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/494,714 filed Apr. 24, 2017, which claims priority to and the benefitof U.S. Provisional Application No. 62/332,043 filed May 5, 2016. Thedisclosure of each of the foregoing applications are hereby incorporatedby reference in its entirety herein.

BACKGROUND Technical Field

The present disclosure relates to systems and methods for simultaneousactivation of two or more electrosurgical instruments powered by asingle electrosurgical generator. In particular, the present disclosurerelates to an electrosurgical generator configured to prevent powersurges during simultaneous activation and deactivation of multipleelectrosurgical instruments.

Background of Related Art

Electrosurgery involves application of high radio frequency (“RF”)electrical current to a surgical site to cut, ablate, desiccate, orcoagulate tissue. In monopolar electrosurgery, a source or activeelectrode delivers radio frequency alternating current from theelectrosurgical generator to the targeted tissue. A patient returnelectrode is placed remotely from the active electrode to conduct thecurrent back to the generator.

In bipolar electrosurgery, return and active electrodes are placed inclose proximity to each other such that an electrical circuit is formedbetween the two electrodes (e.g., in the case of an electrosurgicalforceps). In this manner, the applied electrical current is limited tothe body tissue positioned between the electrodes. Accordingly, bipolarelectrosurgery generally involves the use of instruments where it isdesired to achieve a focused delivery of electrosurgical energy betweentwo electrodes positioned on the instrument, e.g. forceps or the like.

Some conventional electrosurgical generators allow for use of two ormore electrosurgical instruments coupled to a single output rail of theelectrosurgical generator. Thus, the electrosurgical generator splitsthe output from the single output rail to each of the instruments. Thisallows multiple surgeons to operate using a single generator. However,for a selected power setting, if both instruments were activatedsimultaneously, each of the instruments receives only a portion of thepower, dependent on impedance of the tissue. Thus, if both instrumentsare operating simultaneously on the tissue having the same impedance,then each instrument only receives half of the selected power setting.In some instances, due to different impedances encountered by each ofthe electrosurgical instruments, some of the instruments may receive toomuch or too little power, as the conventional electrosurgical generatorsare incapable of calculating power output at each channel. Moreover,when the power flow to one of the instruments is deactivated, then theother instrument experiences a power surge as the electrosurgicalgenerator supplies the full amount of power previously supplied to twoinstruments to a single instrument. Accordingly, there is a need for anelectrosurgical generator configured to prevent power surges that occurduring simultaneous deactivation of one of the multiple electrosurgicalinstruments.

SUMMARY

The present disclosure provides an electrosurgical generator including anon-resonant power converter having one or more switching elementscontrolled by a switching waveform (e.g., a pulse-width modulatedwaveform) generated by a controller. The generator also includes one ormore sensors configures to measure voltage and current of the poweroutput by the power converter. The electrosurgical generator includes anadvanced simultaneous operational mode, during which the electrosurgicalgenerator is set to a common power setting for two or moreelectrosurgical instruments coupled to a single output rail. While oneof the electrosurgical instruments is used, e.g., a firstelectrosurgical instrument, the electrosurgical generator operates in astandard power control mode, during which the power is held constantwithin applicable impedance range and voltage and current limits. Duringthis mode, impedance encountered by the first electrosurgical instrumentis continuously calculated and averaged over a period of time, which maybe from about 500 milliseconds (“ms”) to about 1,000 ms. Once the secondelectrosurgical instrument is activated, simultaneously with the firstelectrosurgical instrument, the impedance encountered by the secondelectrosurgical instrument is in parallel with the impedance encounteredby the first electrosurgical instrument, which results in a parallelimpedance. At this point, the electrosurgical generator also calculatesthe total parallel impedance. Using the previously calculated firstimpedance and the total parallel impedance, the generator estimatesand/or calculates the second impedance. The electrosurgical generatorthen adjusts the voltage supplied to one of the first or secondelectrosurgical instrument having the lower impedance to the selectedpower setting. The other electrosurgical instrument, the one having thehigher impedance, receives higher power. Thus, the electrosurgicalgenerator according to the present disclosure allows for simultaneousactivation of multiple electrosurgical instruments based on measuredimpedance without drastic power changes.

According to one embodiment of the present disclosure, anelectrosurgical generator is provided. The electrosurgical generatorincludes: a power supply configured to output a DC waveform; a powerconverter coupled to the power supply and configured to generate a radiofrequency waveform based on the DC waveform; an active terminal coupledto the power converter and configured to couple to a firstelectrosurgical instrument and a second electrosurgical instrument; atleast one sensor coupled to the power converter and configured to senseat least one property of the radio frequency waveform; and a controllercoupled to the power converter. The controller is configured to:determine a first impedance associated with a first electrosurgicalinstrument and a second impedance associated with a secondelectrosurgical instrument based on the at least one property of theradio frequency waveform; and adjust at least one parameter of the radiofrequency waveform based on the first impedance and the secondimpedance.

According to one aspect of the above embodiment, the electrosurgicalgenerator also includes a user interface coupled to the controller, theuser interface configured to receive a user input.

According to one aspect of the above embodiment, the controller isfurther configured to adjust the at least one parameter of the radiofrequency waveform based on the user input.

According to one aspect of the above embodiment, the electrosurgicalgenerator also includes a return terminal coupled to the powerconverter, wherein the return terminal is configured to couple to atleast one return electrode pad. The active terminal is furtherconfigured to couple to a first monopolar electrosurgical instrument anda second monopolar electrosurgical instrument.

According to one aspect of the above embodiment, the at least oneproperty is power.

According to one aspect of the above embodiment, the controller isfurther configured to adjust the power of the radio frequency waveformsuch that the power delivered to each of the first electrosurgicalinstrument and the second electrosurgical instrument is between 50% and100% of the adjusted power.

According to another embodiment of the present disclosure, anelectrosurgical system is disclosed. The electrosurgical systemincludes: a first electrosurgical instrument; a second electrosurgicalinstrument; and an electrosurgical generator. The electrosurgicalgenerator includes a power supply configured to output a DC waveform; apower converter coupled to the power supply and configured to generate aradio frequency waveform based on the DC waveform; an active terminalcoupled to the power converter and configured to couple to the firstelectrosurgical instrument and the second electrosurgical instrument; atleast one sensor coupled to the power converter and configured to senseat least one property of the radio frequency waveform; and a controllercoupled to the power converter. The controller configured to: determinea first impedance associated with the first electrosurgical instrumentand a second impedance associated with the second electrosurgicalinstrument based on the at least one property of the radio frequencywaveform; and adjust power of the radio frequency waveform based on thefirst impedance and the second impedance.

According to one aspect of the above embodiment, electrosurgicalgenerator further includes a user interface coupled to the controller,the user interface is configured to receive a user input.

According to one aspect of the above embodiment, the controller isfurther configured to adjust the power of the radio frequency waveformbased on the user input.

According to one aspect of the above embodiment, the electrosurgicalgenerator further includes a return terminal coupled to the powerconverter, the return terminal is configured to couple to at least onereturn electrode pad.

According to one aspect of the above embodiment, the active terminal isfurther configured to couple to a first monopolar electrosurgicalinstrument and a second monopolar electrosurgical instrument.

According to one aspect of the above embodiment, the firstelectrosurgical instrument is activated prior to the secondelectrosurgical instrument.

According to one aspect of the above embodiment, the at least one sensoris configured to measure the first impedance prior to activation of thesecond electrosurgical instrument.

According to one aspect of the above embodiment, the at least one sensoris configured to measure total impedance after activation of the firstelectrosurgical instrument and the second electrosurgical instrument.

According to one aspect of the above embodiment, the controller isconfigured to determine the second impedance based on the totalimpedance and the first impedance.

According to one aspect of the above embodiment, the controller isfurther configured to adjust the power such that the power delivered toone of the first electrosurgical instrument or the secondelectrosurgical instrument having a lower impedance does not exceed theadjusted power.

According to one aspect of the above embodiment, the controller furtherconfigured to adjust the power such that the power delivered to one ofthe first electrosurgical instrument or the second electrosurgicalinstrument having a higher impedance is more than half of the adjustedpower.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be understood by reference to theaccompanying drawings, when considered in conjunction with thesubsequent, detailed description, in which:

FIG. 1 is a perspective view of an electrosurgical system according toan embodiment of the present disclosure;

FIG. 2 is a front view of an electrosurgical generator of theelectrosurgical system of FIG. 1 according to an embodiment of thepresent disclosure;

FIG. 3 is a schematic diagram of the electrosurgical system of FIG. 1according to an embodiment of the present disclosure;

FIG. 4 is a flow chart of a method for controlling the electrosurgicalgenerator FIG. 2 according to an embodiment of the present disclosure;and

FIG. 5 is an impedance and power plot for simultaneously activating twoelectrosurgical instruments according to an embodiment of the presentdisclosure.

DETAILED DESCRIPTION

Particular embodiments of the present disclosure will be described belowwith reference to the accompanying drawings. In the followingdescription, well-known functions or constructions are not described indetail to avoid obscuring the present disclosure in unnecessary detail.Those skilled in the art will understand that the present disclosure maybe adapted for use with any electrosurgical instrument. It should alsobe appreciated that different electrical and mechanical connections andother considerations may apply to each particular type of instrument.

Briefly, an electrosurgical generator according to the presentdisclosure may be used in monopolar and/or bipolar electrosurgicalprocedures, including, for example, cutting, coagulation, ablation, andvessel sealing procedures. The generator may include a plurality ofoutputs for interfacing with various electrosurgical instruments (e.g.,monopolar instruments, return electrode pads, bipolar electrosurgicalforceps, footswitches, etc.). Further, the generator includes electroniccircuitry configured to generate radio frequency energy specificallysuited for powering electrosurgical instruments operating in variouselectrosurgical modes (e.g., cut, blend, coagulate, division withhemostasis, fulgurate, spray, etc.) and procedures (e.g., monopolar,bipolar, vessel sealing).

Referring to FIG. 1 an electrosurgical system 10 is shown which includesone or more monopolar electrosurgical instruments 20′ and 20″ having oneor more active electrodes 23′ and 23″ (e.g., electrosurgical cuttingprobe, ablation electrode(s), etc.) for treating tissue of a patient.Electrosurgical alternating RF current is supplied to the instruments20′ and 20″ by a generator 200 via supply lines 24′ and 24″,respectively, that are connected to an active terminal 230 (FIG. 3) ofthe generator 200, allowing the instruments 20′ and 20″ to cut,coagulate, and/or otherwise treat tissue. The alternating RF current isreturned to the generator 200 through a return electrode pad 26 via areturn line 28 at a return terminal 232 (FIG. 3) of the generator 200.The system 10 may include a plurality of return electrode pads 26 that,in use, are disposed on a patient to minimize the chances of tissuedamage by maximizing the overall contact area with the patient. Inaddition, the generator 200 and the return electrode pads 26 may beconfigured for monitoring tissue-to-patient contact to ensure thatsufficient contact exists therebetween. In embodiments, the system 10may also include one or more bipolar electrosurgical instruments, forexample, a bipolar electrosurgical forceps (not shown), having one ormore electrodes for treating tissue of a patient. In furtherembodiments, the generator 200 according to the present disclosure mayalso be configured to simultaneously activate bipolar electrosurgicalinstruments in a manner described below.

With reference to FIG. 2, a front face 240 of the generator 200 isshown. The generator 200 may include a plurality of ports 250-262 toaccommodate various types of electrosurgical instruments. The generator200 includes a user interface 241 having one or more display screens242, 244, 246 for providing the user with variety of output information(e.g., intensity settings, treatment complete indicators, etc.). Each ofthe screens 242, 244, 246 is associated with a corresponding port250-262. The generator 200 includes suitable input controls (e.g.,buttons, activators, switches, touch screen, etc.) for controlling thegenerator 200. The screens 242, 244, 246 are also configured as touchscreens that display a corresponding menu for the instruments (e.g.,more monopolar electrosurgical instruments 20′ and 20″, electrosurgicalforceps, etc.). The user then adjusts inputs by simply touchingcorresponding menu options.

Screen 242 controls monopolar output and the instruments connected tothe ports 250 and 252. Port 250 is configured to couple to a monopolarelectrosurgical instrument (e.g., electrosurgical instruments 20′ and20″) and port 252 is configured to couple to a foot switch (not shown).The foot switch may be used to provide for additional inputs (e.g.,replicating inputs of the generator 200). Screen 244 controls monopolarand bipolar output and the instruments connected to the ports 256 and258. Port 256 is configured to couple to other monopolar instruments.Port 258 is configured to couple to a bipolar instrument (not shown).

Screen 246 controls the electrosurgical forceps that may be plugged intoone of the ports 260 and 262, respectively. The generator 200 outputsenergy through the ports 260 and 262 suitable for sealing tissue graspedby the electrosurgical forceps. In particular, screen 246 outputs a userinterface that allows the user to input a user-defined intensity settingfor each of the ports 260 and 262. The user-defined setting may be anysetting that allows the user to adjust one or more energy deliveryparameters, such as power, current, voltage, energy, etc. or sealingparameters, such as energy rate limiters, sealing duration, etc. Theactive and return terminals 230 and 232 (FIG. 3) may be coupled to anyof the desired ports 250-262. In embodiments, the active and returnterminals 230 and 232 may be coupled to the ports 250-262.

With reference to FIG. 3, the generator 200 includes a controller 224, apower supply 227, and a power converter 228. The power supply 227 may bea high voltage, DC power supply connected to an AC source (e.g., linevoltage) and provides high voltage, DC power to the power converter 228,which then converts high voltage, DC power into RF energy and deliversthe energy to the active terminal 230. The energy is returned theretovia the return terminal 232. In particular, electrosurgical energy forenergizing the monopolar electrosurgical instruments 20′ and 20″ coupledto ports 250 and 256 is delivered through the active terminal 230 andreturned through the return electrode pad 26 coupled to the port 254,which in turn, is coupled to the return terminal 232. The active andreturn terminals 230 and 232 are coupled to the power converter 228through an isolation transformer 229. The isolation transformer 229includes a primary winding 229 a coupled to the power converter and asecondary winding 229 b coupled to the active and return terminals 230and 232.

The generator 200 also includes a DC-DC buck converter 301 coupled tothe power supply 227. Furthermore, an inductor 303 is electricallycoupled to the DC-DC buck converter 301 and the power converter 228. Theinductor 303 may have a relatively large inductance which smoothes thecurrent supplied to the power converter 228, such that the inductor 303is configured to supply relatively constant current to the powerconverter 228. The output of power converter 228 transmits currentthrough an isolation transformer 229 to the load e.g., tissue beingtreated.

The power converter 228 is configured to operate in a plurality ofmodes, during which the generator 200 outputs corresponding waveformshaving specific duty cycles, peak voltages, crest factors, etc. It isenvisioned that in other embodiments, the generator 200 may be based onother types of suitable power supply topologies. Power converter 228 maybe a resonant RF amplifier or a non-resonant RF amplifier, as shown. Anon-resonant RF amplifier, as used herein, denotes an amplifier lackingany tuning components, i.e., conductors, capacitors, etc., disposedbetween the power converter and the load, e.g., tissue.

The controller 224 includes a processor (not shown) operably connectedto a memory (not shown), which may include one or more of volatile,non-volatile, magnetic, optical, or electrical media, such as read-onlymemory (ROM), random access memory (RAM), electrically-erasableprogrammable ROM (EEPROM), non-volatile RAM (NVRAM), or flash memory.The processor may be any suitable processor (e.g., control circuit)adapted to perform the operations, calculations, and/or set ofinstructions described in the present disclosure including, but notlimited to, a hardware processor, a field programmable gate array(FPGA), a digital signal processor (DSP), a central processing unit(CPU), a microprocessor, and combinations thereof. Those skilled in theart will appreciate that the processor may be substituted for by usingany logic processor (e.g., control circuit) adapted to perform thecalculations and/or set of instructions described herein.

The controller 224 includes an output port that is operably connected tothe power supply 227 and/or power converter 228 allowing the processorto control the output of the generator 200 according to either openand/or closed control loop schemes. A closed loop control scheme is afeedback control loop, in which a plurality of sensors measure a varietyof tissue and energy properties (e.g., tissue impedance, tissuetemperature, output power, current and/or voltage, etc.), and providefeedback to the controller 224. The controller 224 then controls thepower supply 227 and/or power converter 228, which adjusts the DC and/orpower supply, respectively.

The generator 200 according to the present disclosure may also include aplurality of sensors 310. In the embodiment illustrated in FIG. 3, thesensors 310 are coupled to a rail 305, which couples the power converter228 to the primary winding 229 a of the transformer 229. Thus, thesensors 310 are configured to sense voltage, current, and otherelectrical properties of energy supplied to the active and returnterminals 230 and 232 through the rail 305.

In further embodiments, the sensors 310 may be coupled to the powersupply 227, DC-DC buck converter 301, and/or the inductor 303, and maybe configured to sense properties of DC current supplied to the powerconverter 228. The controller 224 also receives input signals from theinput controls of the generator 200 and/or the instruments 20′ and 20″,and/or electrosurgical forceps 30. The controller 224 utilizes the inputsignals to adjust power outputted by the generator 200 and/or performsother control functions thereon.

The DC-DC buck converter 301 includes a switching element 301 a andpower converter 228 includes a plurality of switching elements 228 a-228d arranged in an H-bridge topology. In embodiments, power converter 228may be configured according to any suitable topology including, but notlimited to, half-bridge, full-bridge, push-pull, and the like. Suitableswitching elements include voltage-controlled devices such astransistors, field-effect transistors (FETs), combinations thereof, andthe like. In embodiments, the FETs may be formed from gallium nitride,aluminum nitride, boron nitride, silicone carbide, or any other suitablewide bandgap materials.

The controller 224 is in communication with both DC-DC buck converter301 and power converter 228, in particular, the switching elements 301 aand 228 a-228 d, respectively. Controller 224 is configured to outputcontrol signals, which may be a pulse-width modulated (“PWM”) signal, toswitching elements 301 a and 228 a-228 d. In particular, controller 224is configured to modulate a control signal d₁ supplied to switchingelement 301 a of DC-DC buck converter 301 and control signal d₂ suppliedto switching elements 228 a-228 d of power converter 228. Additionally,controller 224 is configured to calculate power characteristics ofgenerator 200, and control generator 200 based at least in part on themeasured power characteristics including, but not limited to, currentpassing through the inductor 303, DC output of the DC-DC buck converter301, and the voltage and current at the output of power converter 228.

With reference to FIG. 4, a method 400 according to the presentdisclosure for controlling the generator 200 during simultaneousactivation of electrosurgical instruments 20′ and 20″ is described.Method 400 is also described below concurrently with FIG. 5, which showsa combined plot of impedance encountered by each of the electrosurgicalinstruments 20′ and 20″ and power delivered thereto.

Initially, the electrosurgical instruments 20′ and 20″ are coupled tothe active terminal 230 of the generator 200 through the ports 250 and256. The user may select a desired electrosurgical mode (e.g., cut,blend, coagulate, division with hemostasis, fulgurate, spray, etc.). Theuser also selects the power/intensity setting at which theelectrosurgical instrument 20′ is operated through the user interface241. Thereafter, the electrosurgical instrument 20′ is activated bysignaling the generator 200 to supply electrical power. In response,electrosurgical energy is supplied to the electrosurgical instrument20′, during which the sensors 310 continually monitor electricalproperties of the supplied energy, such as voltage and current. Themonitored voltage and current values are supplied to the controller 224,which calculates the impedance encountered by the electrosurgicalinstrument 20′ during treatment. In embodiments, the controller 224 maycontinuously calculate impedance based on the measured voltage andcurrent values to obtain first instrument impedance Z1 (e.g., impedanceof the electrosurgical instrument 20′) as shown in FIG. 5. Thecalculated impedance may be averaged to provide a moving average over adefined time period. The time period for the moving impedance averagemay be from about 100 milliseconds (ms) to about 2,000 ms, inembodiments, the time period may be from about 500 ms to about 1,000 ms.

The second electrosurgical instrument 20″ may be activatedsimultaneously with or after the first electrosurgical instrument 20′.As the second electrosurgical instrument 20″ contacts tissue, the tissueimpedance encountered by the second electrosurgical instrument 20″, Z2,is in parallel with impedance Z1 of the first electrosurgical instrument20′. As described above, the sensors 310 measure voltage and currentthrough the rail 305, which supplies energy to the active terminal 230,to which both of the first and second electrosurgical instrument 20′ and20″ are coupled. Accordingly, the sensors 310 are capable of determiningvoltage and current for the combined power supplied to the first andsecond electrosurgical instruments 20′ and 20″. The controller 224calculates the total impedance, Ztotal, based on the total measuredvoltage and current. The Ztotal value is based on the parallelcombination of Z1 and Z2. Accordingly, the controller 224 is configuredto calculate Z2, which cannot be measured directly by the sensors 310 asthe first and second electrosurgical instruments 20′ and 20″ share acommon output, namely the active terminal 230 through the rail 305. Inparticular, the controller 224 is configured to calculate Z2 based onthe following formulas (I) and (II):Ztotal=Z1*Z2/(Z1+Z2)  (I)Z2=Z1*Ztotal/(Z1−Ztotal)  (II)

In formulas (I) and (II), Z1 is the impedance calculated based onmeasured voltage and current when only one electrosurgical instrument(e.g., first electrosurgical instrument 20′) is activated, Ztotal is theimpedance calculated based on measured voltage and current when bothelectrosurgical instruments 20′ and 20″ are activated, and Z2 is theimpedance encountered by the second electrosurgical instrument 20″.

Once the controller 224 calculates Z2, both Z1 and Z2 are known, thecontroller 224 adjusts the power output of the power converter 228 basedon the selected power setting and the impedance of both of theelectrosurgical instruments 20′ and 20″. In particular, the controller224 adjusts the power to provide for a change in impedance due toaddition of the impedance encountered by the second electrosurgicalinstrument 20″. However, power is adjusted not to exceed the initialpower setting and to ensure that the electrosurgical instrument with thelower impedance receives the power at the initial power setting. Thepower is also adjusted such that the other electrosurgical instrumentreceives more than half of the selected power setting.

The power and impedance plots for each of the electrosurgicalinstruments 20′ and 20″ are described in further detail below withrespect to FIG. 5. In particular, plots P1 and Z1 illustrate exemplarypower delivered to and the measured impedance encountered by the firstelectrosurgical instrument 20′, respectively. The electrosurgicalinstrument 20′ is activated at the selected power setting of about 40watts and the impedance is constant at about 2,000 ohms. At about 3seconds, the second electrosurgical instrument 20″ is activated and thecontroller 224 determines that the impedance of the secondelectrosurgical instrument 20″ is about 1,500 ohms, based on the totalimpedance, Ztotal. Since the addition of another electrosurgicalinstrument in parallel results in decrease in impedance, the controller224 signals the power converter to adjust its output such that thesecond electrosurgical instrument 20″, which has the lower impedance,receives the power at the selected setting of about 40 watts. Based onthat setting, the first electrosurgical instrument 20′ receives about 30watts, which is larger than 50% of the initial setting of 40 watts. Thiscalculation and adjustment in power prevents large swings in power, suchthat when the first electrosurgical instrument 20′ is deactivated atabout 8 seconds, the second electrosurgical instrument 20″ continues toreceive power at the initial power setting of about 40 watts, ratherthan receiving the higher combined power for both of the electrosurgicalinstruments 20′ and 20″.

In embodiments, the generator 200 may include individual rails for eachof the ports 250 and 256 and the sensors 310 may be coupled to each ofthe rails to monitor current and voltage therein. The controller 224 maythen calculate power for each rail individually and signal the powerconverter 228 to adjust the power dynamically to match the set power oneach of the rail as described above with respect to the embodiment ofFIG. 3. In particular, the controller 224 signals the power converter228 to adjust the power dynamically at the rail having the highestcurrent not to exceed the power setting.

While several embodiments of the disclosure have been shown in thedrawings and/or described herein, it is not intended that the disclosurebe limited thereto, as it is intended that the disclosure be as broad inscope as the art will allow and that the specification be read likewise.Therefore, the above description should not be construed as limiting,but merely as exemplifications of particular embodiments. Those skilledin the art will envision other modifications within the scope and spiritof the claims appended hereto.

What is claimed is:
 1. An electrosurgical generator comprising: anactive terminal configured to couple to a first electrosurgicalinstrument and a second electrosurgical instrument; a power supplyconfigured to output a DC waveform; a power converter coupled to thepower supply and to the active terminal, the power converter configuredto generate a radio frequency waveform based on the DC waveform and tosupply the radio frequency waveform simultaneously to the firstelectrosurgical instrument and the second electrosurgical instrument; asensor coupled to the power converter and configured to sense at leastone property of the radio frequency waveform; and a controller coupledto the power converter, the controller configured to: determine a firstimpedance associated with the first electrosurgical instrument;determine a total impedance of the first and second electrosurgicalinstruments; determine a second impedance associated with the secondelectrosurgical instrument based on the total impedance and the firstimpedance; and adjust at least one parameter of the radio frequencywaveform based on the first impedance and the second impedance.
 2. Theelectrosurgical generator according to claim 1, further comprising: auser interface coupled to the controller, the user interface configuredto receive a user input.
 3. The electrosurgical generator according toclaim 2, wherein the controller is further configured to adjust the atleast one parameter of the radio frequency waveform based on the userinput.
 4. The electrosurgical generator according to claim 1, furthercomprising a return terminal coupled to the power converter, wherein thereturn terminal is configured to couple to at least one return electrodepad.
 5. The electrosurgical generator according to claim 4, wherein theactive terminal is further configured to couple to a first monopolarelectrosurgical instrument and a second monopolar electrosurgicalinstrument.
 6. The electrosurgical generator according to claim 1,wherein the controller is further configured to adjust the power of theradio frequency waveform such that the power delivered to each of afirst electrosurgical instrument and a second electrosurgical instrumentis between 50% and 100% of the adjusted power.
 7. An electrosurgicalsystem comprising: a first electrosurgical instrument; a secondelectrosurgical instrument; and an electrosurgical generator including:an active terminal configured to couple to the first electrosurgicalinstrument and the second electrosurgical instrument; a power supplyconfigured to output a DC waveform; a power converter coupled to thepower supply and to the active terminal, the power converter configuredto generate a radio frequency waveform based on the DC waveform andsupply the radio frequency waveform simultaneously to the firstelectrosurgical instrument and the second electrosurgical instrument; asensor coupled to the power converter and configured to sense at leastone property of the radio frequency waveform; and a controller coupledto the power converter, the controller configured to: determine a firstimpedance associated with the first electrosurgical instrument;determine a total impedance of the first and second electrosurgicalinstruments; determine a second impedance associated with the secondelectrosurgical instrument based on the total impedance and the firstimpedance; and adjust power of the radio frequency waveform based on thefirst impedance and the second impedance.
 8. The electrosurgical systemaccording to claim 7, wherein the electrosurgical generator furtherincludes a user interface coupled to the controller, the user interfaceis configured to receive a user input.
 9. The electrosurgical systemaccording to claim 8, wherein the controller is further configured toadjust the power of the radio frequency waveform based on the userinput.
 10. The electrosurgical system according to claim 7, wherein theelectrosurgical generator further includes a return terminal coupled tothe power converter, the return terminal is configured to couple to atleast one return electrode pad.
 11. The electrosurgical system accordingto claim 10, wherein the active terminal is further configured to coupleto a first monopolar electrosurgical instrument and a second monopolarelectrosurgical instrument.
 12. The electrosurgical system according toclaim 7, wherein the controller is configured to activate the firstelectrosurgical instrument prior to the second electrosurgicalinstrument.
 13. The electrosurgical system according to claim 12,wherein the sensor is configured to measure the first impedance prior toactivation of the second electrosurgical instrument.
 14. Theelectrosurgical system according to claim 7, wherein the sensor isconfigured to measure the total impedance after activation of the firstelectrosurgical instrument and the second electrosurgical instrument.15. The electrosurgical system according to claim 7, wherein thecontroller is further configured to determine which electrosurgicalinstrument of the first or second electrosurgical instruments has alower impedance and adjust the power such that the power delivered tothe electrosurgical instrument having the lower impedance does notexceed the adjusted power.
 16. The electrosurgical system according toclaim 7, wherein the controller is further configured to determine whichelectrosurgical instrument of the first or second electrosurgicalinstruments has a higher impedance value and adjust the power such thatthe power delivered to the electrosurgical instrument having the higherimpedance is more than half of the adjusted power.
 17. A method forsimultaneous activation of two or more electrosurgical instruments, themethod comprising: coupling a first electrosurgical instrument and asecond electrosurgical instrument to an active terminal of anelectrosurgical generator; outputting a DC waveform at a power supply ofthe electrosurgical generator; generating a radio frequency waveformbased on the DC waveform at a power converter coupled to the powersupply and the active terminal of the electrosurgical generator;supplying the radio frequency waveform simultaneously to the firstelectrosurgical instrument and the second electrosurgical instrument;sense at least one property of the radio frequency waveform through atleast one sensor coupled to the power converter; determining a firstimpedance associated with the first electrosurgical instrument;determining a total impedance of the first and second electrosurgicalinstruments; determine a second impedance associated with the secondelectrosurgical instrument based on the total impedance and the firstimpedance; and adjusting power of the radio frequency waveform based onthe first impedance and the second impedance.